Note on Linker Script file

In an embedded system, especially in bare metal systems, while programming, we come across a file called linker script file ( .lds or .ld)

Curious to know what is the purpose of this file is, let’s see.?

The Main purpose of the linker script file is to describe how the different sections in the input files ( object files ) should be mapped into the output file also to control the memory layout of the output file ( executable file).?

Let’s go in deep. In bare metal embedded systems, linker does 2 jobs while linking multiple object files.?

1. Linking the multiple files ( resolving the symbols ) and producing a single relocatable file
2. Locator - The relocatable file is an input to this step and the locator maps the application code and data into proper addresses with the help of a linker script file. Basically, the locator is to assign specific address locations to the object file according to the memory map of the microcontroller. After performing address allocation, the locator produces an executable file that we can install on the embedded device.?The linker script has this information and helps the locator to do this step.?

Note:

In Operating system hosted environment, linker does linking only, locator job is done by OS ( loader ).